Exemplary embodiments of the invention relate to a motor vehicle drive train device.
European patent document EP 1 438 525 B1 discloses a motor vehicle drive train device having a multi-group transmission, which includes a main group, a front-mounted group upstream from the main group, and a downstream group downstream from the main group, and a control and/or regulation unit, the motor vehicle drive train device being provided for shifting, at least in one transmission gear change operation, the front-mounted group and the downstream group into neutral before engaging a target gear in the main group.
A motor vehicle drive train device having a multi-group transmission is likewise known from European patent document EP 2 037 159 A2, related to the same species, which includes a main group, a front-mounted group upstream from the main group, and a downstream group downstream from the main group, and a control and/or regulation unit, the motor vehicle drive train device being provided for shifting, at least in one transmission gear change operation, the front-mounted group and the downstream group into neutral before engaging a target gear in the main group. In addition, this publication discloses that the control and/or regulation unit is provided for shifting the front-mounted group and/or the downstream group into neutral in the transmission gear change operation only after at least partial synchronization of the main group.
Exemplary embodiments of the present invention are directed to enhancing shifting comfort. Exemplary embodiments of the present invention are directed to a motor vehicle drive train device having a multi-group transmission which includes a main group, a front-mounted group upstream from the main group, and/or a downstream group downstream from the main group, and a control and/or regulation unit, the motor vehicle drive train device being for shifting, at least in one transmission gear change operation, the front-mounted group and/or the downstream group into neutral before engaging a target gear in the main group.
In addition, the control and/or regulation unit is provided for shifting the front-mounted group and/or the downstream group into neutral in the transmission gear change operation only after at least partial synchronization of the main group. In this way an advantageous point in time may be found for shifting the front-mounted group and/or the downstream group into neutral, as the result of which active mass moments of inertia for engaging the target gear may be reduced in a particularly advantageous manner. A difference in rotational speeds between shafts and/or components to be synchronized, in particular between a main shaft of the main group and a countershaft, in which it is possible to engage a target gear, in particular a transmission gear opposite to a current direction of travel, without at least significant loss of comfort, may be increased, as the result of which synchronization of the multi-group transmission for engaging the target gear, in particular the transmission gear opposite to the current direction of travel, may be improved, and rattling and/or “shift shock” may be at least reduced. It is thus possible to improve the engagement of the transmission gear opposite to the current direction of travel and/or the shifting of the transmission gear opposite to the current direction of travel. In addition, the likelihood of a tooth-to-tooth position may be reduced, thus allowing increased shifting comfort for the target gear and enhanced customer satisfaction.
A “multi-group transmission” is understood in particular to mean a transmission that is composed of a combination of one-, two-, or multi-stage single gears.
A “main group” is understood in particular to mean a single gear which is intended for providing and/or setting at least one forward transmission gear and at least one reverse transmission gear, and/or has at least two settable gear ratios that are opposite one another, and which thus differ in their algebraic signs.
A “downstream group” is understood in particular to mean a single gear downstream from the main group that provides at least two different gear ratios for increasing the number of gears, and/or which is intended for providing a fast transmission gear and a slow transmission gear provided by means of the main group.
A “front-mounted group” is understood in particular to mean a single gear situated upstream from the main group and which provides at least two different gear ratios in order to increase the number of gears. A gear ratio may preferably also have a value of 1.
The terms “upstream from” and “downstream from” are understood in particular to mean in relation to a flow of force that is present for drive wheels driven by the drive machine and/or for an active drive machine, i.e., which preferably provides drive torque, and which is in drive connection with the multi-group transmission.
A “control and/or regulation unit” is understood in particular to mean a unit including at least one control device. A “control device” is understood in particular to mean a unit having a processor unit and a memory unit as well as an operating program that is stored in the memory unit. In principle, the control and/or regulation unit may include multiple interconnected control devices which preferably are provided for communicating with one another via a bus system, such as a CAN bus system.
A “transmission gear change operation” is understood in particular to mean an operation in which, starting from a transmission gear that is currently engaged, i.e., preferably an actual gear, a target gear is shifted during travel, the operation advantageously being initiated by a driver of the motor vehicle which has the motor vehicle drive train device and/or by the shifting instruction triggered by the control and/or regulation unit.
The term “engaging a target gear” is understood in particular to mean setting a gear ratio associated with the corresponding target gear within the main group, and/or establishing a torque-transmitting connection between all coupling units of the main group which are provided for the corresponding target gear. The target gear is preferably engaged by the main group.
The term “shifting a target gear” is understood in particular to mean setting a torque-transmitting connection between a drive machine and drive wheels of the motor vehicle when the target gear is engaged. An operation in which the target gear is shifted preferably constitutes an operation in which the target gear is engaged. The shifting of the target gear preferably constitutes disengagement of an actual gear, engagement of the corresponding target gear, and lastly, engagement of a starting clutch for establishing the torque-transmitting connection between the drive machine and the drive wheels.
The term “front-mounted group shifted into neutral” is understood in particular to mean an actuation state of the front-mounted group in which torque transmission by the front-mounted group is prevented, the front-mounted group preferably having a defined neutral position or being capable of being brought into a position in which the torque transmission is prevented. For a front-mounted group shifted into neutral, the main group is preferably drive-decoupled from a transmission input shaft.
The term “downstream group shifted into neutral” is understood in particular to mean an actuation state of the downstream group in which transmission of torque by the downstream group is prevented, for this purpose the downstream group preferably having a defined neutral position or being capable of being brought into a position in which the transmission of torque is prevented. For a downstream group shifted into neutral, the main group is preferably drive-decoupled from the transmission output shaft.
The term “shifting after at least partial synchronization of the main group” is understood in particular to mean shifting when the main group is at least partially synchronized and/or after a start of a synchronization phase of the main group, whereby the synchronization and/or the synchronization phase may preferably also already be concluded.
The term “synchronization of the main group” is understood in particular to mean adjustment of speed differences between at least two shafts to be synchronized, preferably a main shaft and a countershaft, and/or components, preferably claws, of the main group. The control and/or regulation unit preferably delays the shifting of the front-mounted group and/or the downstream group into neutral until a point in time when the main group is at least partially synchronized.
A “transmission gear opposite to the current direction of travel” is understood in particular to mean a target gear provided for a direction of travel that is oriented opposite to a direction of travel for which an actual gear, which is shifted when there is a request for the target gear, is provided. For an engaged forward transmission gear, and thus for forward travel, the transmission gear opposite to the current direction of travel is preferably provided as the reverse transmission gear, and for an engaged reverse transmission gear, and thus for reverse travel, the transmission gear opposite to the current direction of travel is preferably provided as the forward transmission gear.
The term “forward transmission gear” basically includes all forward transmission gears that are shiftable by means of the multi-group transmission, in particular a starting transmission gear that is provided for forward travel, and thus, a so-called first forward transmission gear.
The term “reverse transmission gear” basically includes all reverse transmission gears that are shiftable by means of the multi-group transmission, in particular a starting transmission gear that is provided for reverse travel.
A “current direction of travel” is understood in particular to mean a direction of travel in which the motor vehicle is moving when the transmission gear change operation is initiated, and thus, during the shifting instruction and/or when the transmission gear is requested.
The term “provided” is understood in particular to mean specially programmed, designed, equipped, configured, and/or situated.
According to the invention, the control and/or regulation unit is provided for shifting the downstream group in the transmission gear change operation when the front-mounted group is shifted into neutral. The mass moment of inertia during shifting of the downstream group may thus be reduced, the main gear or the main group being shifted at the same time. The control and/or regulation unit preferably shifts the downstream group into its target position after the target gear is engaged, with the front-mounted group shifted into neutral.
Furthermore, the control and/or regulation unit is provided for shifting the front-mounted group and/or the downstream group into neutral in the transmission gear change operation only shortly before the target gear is engaged. As a result, the front-mounted group and/or the downstream group may be shifted into neutral at a particularly advantageous point in time. The control and/or regulation unit preferably delays the shifting of the front-mounted group and/or the downstream group into neutral until shortly before the target gear is engaged. The term “shortly before the target gear is engaged” is understood in particular to mean 0.5 second maximum, advantageously 0.2 second maximum, and particularly advantageously 0.1 second maximum, before the target gear is engaged. The engagement of the target gear in the main group and the shifting of the front-mounted group and/or the downstream group into neutral preferably lie in a time window of 0.5 second maximum, advantageously 0.2 second maximum, and particularly advantageously 0.1 second maximum.
Additionally, the control and/or regulation unit is provided for shifting the front-mounted group and/or the downstream group into neutral in the transmission gear change operation during a synchronization phase of the main group, as the result of which the target gear may be shifted particularly rapidly. A “synchronization phase” is understood in particular to mean a phase in the transmission gear change operation in which the main group is synchronized for engaging the target gear. The control and/or regulation unit preferably shifts the front-mounted group and/or the downstream group into neutral shortly before or upon conclusion of the synchronization phase. In principle, the control and/or regulation unit may shift the front-mounted group and/or the downstream group into neutral only shortly after the synchronization phase.
In addition, it is advantageous when the control and/or regulation unit is provided for shifting first the downstream group, and then the front-mounted group, into a target position in the transmission gear change operation after the target gear is engaged. A particularly advantageous transmission gear change operation may be provided in this way. A “target position of the downstream group” is understood in particular to mean a shift position of the downstream group in which a torque is transmitted by the downstream group. A “target position of the front-mounted group” is understood in particular to mean a shift position of the front-mounted group in which a torque is transmitted by the front-mounted group.
Furthermore, it is advantageous when the control and/or regulation unit is provided for shifting the front-mounted group and/or the downstream group into neutral in the transmission gear change operation when the main group is shifted into neutral. The transmission gear change operation may be further improved in this way. A “main group shifted into neutral” is understood in particular to mean that a transmission gear is not engaged within the main group. The control and/or regulation unit advantageously shifts the front-mounted group and/or the downstream group into neutral when the transmission gear is disengaged and/or after the actual gear is disengaged.
In addition, it is advantageous when the motor vehicle drive train device has a synchronization unit provided for providing a braking torque and/or a drive torque in order to synchronize the main group. The main group may thus be synchronized in a particularly advantageous manner. The control and/or regulation unit advantageously controls the synchronization unit in order to synchronize the main group. The control and/or regulation unit preferably shifts the front-mounted group and/or the downstream group into neutral during the control of the synchronization unit. The term “control of the synchronization unit” is understood in particular to mean a setting of the braking torque and/or the drive torque to be greater than zero.
The main group is particularly preferably designed as an unsynchronized claw clutch transmission group. A cost-effective multi-group transmission may be provided in this way. A “claw clutch transmission group” is understood in particular to mean a single gear having coupling units designed as claw clutches and/or claw brakes for setting the corresponding gear ratios. For engaging the transmission gears, the main group advantageously has positive-fit claw clutches that are unsynchronized, i.e., free of synchronous elements, and which are preferably engaged and disengaged by means of a sliding sleeve.
In addition, it is advantageous when the front-mounted group and/or the downstream group has/have a synchronized design, thus allowing further enhancement of shifting comfort. A “front-mounted group having a synchronized design” is understood in particular to mean a front-mounted group which for setting the corresponding gear ratio has positive-fit coupling units, preferably claw clutches, which are synchronized, i.e., having synchronous elements, and which are preferably engaged and disengaged by means of a sliding sleeve. A “downstream group having a synchronized design” is understood in particular to mean a downstream group which for setting the corresponding gear ratio has positive-fit coupling units, preferably claw clutches, which are synchronized, i.e., having synchronous elements, and which are preferably engaged and disengaged by means of a sliding sleeve.
In addition, a shifting method for a multi-group transmission of a motor vehicle drive train device, in particular a motor vehicle drive train device according to the invention, is proposed in which, in at least in one transmission gear change operation, a front-mounted group and/or a downstream group is/are shifted into neutral before engaging a target gear in a main group, the front-mounted group and/or the downstream group being shifted into neutral in the transmission gear change operation only after at least partial synchronization of the main group. Mass moments of inertia for engaging the target gear may be advantageously reduced in this way.
Further advantages result from the following description of the drawings. One exemplary embodiment of the invention is illustrated in the drawings. The drawings, the description, and the claims contain numerous features in combination. Those skilled in the art will also advantageously consider the features individually and combine them into further meaningful combinations.